Sigmoid notch osseous reconstruction

The purpose of this article is to describe a technique of restoring stability or congruency to the distal radioulnar joint (DRUJ) by osteoplasty or osteotomy of the sigmoid notch, where abnormalities in the osseous anatomy have resulted in DRUJ instability. This technique addresses the osseous cause to DRUJ instability and avoids the need for complex soft tissue procedures to treat chronic volar instability or salvage procedures to treat dorsal instability of the DRUJ associated with an impacted fracture of the dorsal rim of the sigmoid notch.     

Distal radioulnar joint volar instability after ligament reconstruction failure treated with sigmoid notch osteotomy

Because osseous abnormalities result in distal radioulnar joint instability, a sigmoid notch osteotomy is used to restore stability. This article describes a case of distal radioulnar joint volar instability treated with sigmoid notch osteotomy of the volar rim.A 22-year-old man presented with a 9-month history of right wrist pain with volar instability after a fall, which was treated conservatively. He reported a history of remote trauma when he was 7 years old but had been asymptomatic since then. Four months later, he underwent anatomical distal radioulnar joint ligament reconstruction at another hospital after a diagnosis of distal radioulnar joint instability, but the instability had persisted.Computed tomography revealed dynamic volar subluxation of the ulnar head with hypoplasia and a flattened volar lip of the sigmoid notch. Therefore, a sigmoid notch osteotomy of the volar rim was performed. Postoperatively, an above-elbow cast was applied with forearm pronation for 6 weeks. Six months later, the patient had regained 60° of supination and 70° of pronation. He reported minor pain and no instability. Computed tomography scan at 6 months postoperatively revealed union of the osteotomy site and confirmed the maintenance of reduction. The patient returned to work.     

Distal radioulnar joint instability in distal radius fractures: the role of sigmoid notch and triangular fibrocartilage complex revisited

The stabilising effects of various structures of the distal radioulnar joint (DRUJ) have been heavily debated. This biomechanical cadaveric study examined the effects of the volar and dorsal lips of the sigmoid notch and the volar and dorsal aspects of the triangular fibrocartilage complex (TFCC) on DRUJ stability. Sequential fractures of the distal radius and sectioning of the TFCC were performed followed by measurements of ulnar translation with the forearm in pronation, neutral and supination. A dorsal lunate facet fracture created instability in pronation. Lunate facet fractures alone did not create instability in other forearm positions. Sectioning of the volar TFCC after loss of the dorsal TFCC by a dorsal lunate facet fracture caused DRUJ instability with the forearm in neutral position. Sectioning of the dorsal TFCC after loss of the volar TFCC due to a volar lunate facet fracture created instability in neutral and pronated positions.     

Biomechanics of the distal radioulnar joint.

The distal radioulnar joint (DRUJ) is a complex joint involved in pronosupination and ulnocarpal motion and support. The ulnar head, in a rolling, sliding motion, moves from the dorsal to the volar rim of the sigmoid notch as the joint moves from pronation to supination. The triangular fibrocartilage (TFC) is taut first dorsally and then volarly in the same sequence. The ulnar carpus is supported variably, as a function of ulnar length relative to the radial articular surface, by the pole of the distal ulna through the TFC. The TFC does not resist the pistonlike movement of the DRUJ, which occurs under dynamic loading. The coronal alignment of the DRUJ minimizes shear stress on the articular surfaces because of its alignment with the rotational axis of the forearm. Ulnar variance is a factor in the development of several clinical conditions.     

The management of chronic distal radioulnar instability

The stabilizing constraints of the distal radioulnar joint (DRUJ) include its bony geometry and the surrounding soft tissue support. Given the shallow nature of the sigmoid notch, reconstruction of the palmar and dorsal ligamentous sleeve provides the best solution for restoring stability in cases of chronic DRUJ instability. The pertinent anatomy, indications, contraindications, soft tissue stabilizing procedures, and rehabilitation for the management of chronic DRUJ instability are highlighted in this review.     

Volar dislocation of the extensor carpi ulnaris tendon on magnetic resonance imaging is associated with extensor digitorum communis tendon rupture in rheumatoid wrists

PURPOSE: Extensor tendon rupture in rheumatoid wrists is a common problem and causes immediate dysfunction of the digits. The best treatment for tendon rupture may be prophylactic management, although the factors associated with tendon rupture must first be identified. The purpose of this study was to evaluate structures around rheumatoid wrists using magnetic resonance imaging with forearm rotation and to identify factors associated with extensor tendon rupture as indications for prophylactic surgery. METHODS: The subjects were 34 patients (40 wrists) with active rheumatoid arthritis. The extensor digitorum communis (EDC) tendons were ruptured in 15 wrists. Magnetic resonance imaging of the wrists was performed in maximally pronated and supinated positions of the forearm. Axial images of the distal radioulnar joints (DRUJs) were selected to evaluate DRUJ synovitis, dorsal tenosynovitis, volar dislocation of the extensor carpi ulnaris (ECU) tendon, sigmoid notch angle, and the radioulnar ratio (RUR) (ie, the degree of DRUJ subluxation). RESULTS: No significant correlations were found between EDC tendon rupture and DRUJ synovitis, dorsal tenosynovitis, or RUR in pronation. Extensor digitorum communis tendon rupture correlated significantly with volar ECU tendon dislocation, sigmoid notch angle, and RUR in supination. Radioulnar ratio correlated significantly with volar ECU tendon dislocation only in supination and not in pronation. Thus, DRUJ subluxation was advanced even in the supinated wrist with volar ECU tendon dislocation. As a factor associated with EDC tendon rupture, volar ECU tendon dislocation had 87% sensitivity and 76% specificity. CONCLUSIONS: Volar ECU tendon dislocation is associated with increased RUR in supination and EDC tendon rupture. Volar ECU tendon dislocation can thus be considered a factor associated with EDC tendon rupture, and its presence may indicate the need for prophylactic surgical intervention in a subset of rheumatoid arthritis patients.     

Arthroscopic resection of an osteochondral loose body in the distal radioulnar joint: A case report

We report a 34-year-old man who presented with ulnar wrist pain, painful click, and locking during forearm rotation following a motorcycle accident. Plain radiographs showed a loose body in the distal radioulnar joint (DRUJ), deformity of the sigmoid notch and ulnar head, and ulnar minus variant. The DRUJ deformity was assumed to be associated with physeal injury of the distal ulna during childhood. Conservative treatment with a splint and oral analgesics for 3 months failed. During DRUJ arthroscopy, osteoarthritic changes were found, and the loose body was resected using DRUJ arthroscopy. Histological examination showed an osteochondral loose body. The patient remained asymptomatic without recurrence or DRUJ instability 2 years postoperatively.     

Sigmoid notch osteotomy for posttraumatic dorsal dislocation of the distal radioulnar joint: A case report

Instability of the distal radioulnar joint (DRUJ) is associated most commonly with injury to the soft-tissue restraints of that joint, particularly the triangular fibrocartilage complex. The dorsal rim of the sigmoid notch, however, also plays an important role as a bony restraint to dorsal subluxation. We report a case of posttraumatic dorsal dislocation of the DRUJ associated with a depressed fracture of the dorsal rim of the sigmoid notch. This was treated with soft-tissue release and corrective osteotomy of the dorsal rim of the sigmoid notch to restore DRUJ stability and congruency.     

An anatomic reconstruction of the distal radioulnar ligaments for posttraumatic distal radioulnar joint instability

Fourteen patients with posttraumatic distal radioulnar joint instability were treated with a reconstruction of the distal radioulnar ligaments. The technique is anatomically accurate, is reproducible, and requires less dissection than previously described techniques. Candidates for the procedure had joint instability and an irreparable triangular fibrocartilage complex. Ten patients had bidirectional instability. Two patients had a concurrent corrective osteotomy of the distal radius for a malunion. The procedure restored stability and relieved symptoms in 12 of 14 patients at 1 to 4 years' follow-up evaluation. One patient with a deficient sigmoid notch and one with ulnocarpal ligament injury did not achieve full stability. All patients attained near full pronation and supination. The procedure is an effective treatment for an unstable distal radioulnar joint when its articular surfaces are intact and the other wrist ligaments are functional, and it can be used in combination with a distal radius corrective osteotomy.     

Sigmoid notch reconstruction and limited carpal arthrodesis for a severely comminuted distal radius malunion: case report

We present the case of a young patient with a severely comminuted, malunited, intra-articular distal radius fracture and complete disruption of the sigmoid notch. We reconstructed the malunited distal radioulnar joint by osteotomy and repositioning the displaced sigmoid notch fragments through a combined dorsal and volar approach. At the same time, we carried out a radioscapholunate arthrodesis with distal scaphoid excision. We used a free vascularized corticoperiosteal flap from the medial femoral condyle to span the massive bone defect in the radius to obtain union. At the 2.5-year follow-up, the patient had essentially normal function of the distal radioulnar joint (painless, with 85° of active pronation and 75° of supination). He resumed work as a bricklayer without limitations. We conclude that sigmoid notch reconstruction by osteotomy is worthwhile in the setting of malunited distal radius whether or not the radiocarpal joint is reconstructable.     

Reconstruction for DRUJ Instability

The skeletal architecture of the DRUJ provides minimal inherent stability, as the sigmoid notch is shallow and its radius of curvature is 50% greater than that of the ulnar head [Af Ekenstam F, Hagert CG. Anatomical studies on the geometry and stability of the distal radio ulnar joint. Scand J Plast Reconstr Surg 1985;19(1):17–25]. Due to its incongruent articulation, the DRUJ relies strongly on the surrounding soft tissues for stability. The triangular fibrocartilage complex (TFCC) is generally accepted as the major soft tissue stabilizer of the DRUJ of which the volar and dorsal radioulnar ligaments are the primary components. Restoration of the radioulnar ligaments offers the best possibility to restore the normal DRUJ primary constraints and kinematics. This article presents an update of the procedure developed by the senior author that anatomically reconstructs the palmar and dorsal radioulnar ligaments at their anatomic origins and insertions.     

韧带解剖重建术治疗慢性远尺桡关节不稳定

 目的介绍自体掌长肌腱移植、远尺桡韧带解剖重建的适应证、手术方法 及治疗慢性远尺 桡关节(distal radioulnar joint, DRUJ)不稳定的初期随访结果 。方法 2008年 10月至 2009年 6月, 应用 自体掌长肌腱移植、远尺桡韧带解剖重建术治疗 6例慢性 DRUJ不稳定患者。平均年龄 22岁。男 4例, 女 2例。术中取腕背第四、五伸肌鞘管间纵行切口。切开鞘管, 显露 DRUJ背侧部分。横野L冶形切开远尺 桡背侧关节囊, 显露 DRUJ和三角纤维软骨盘。于桡骨远端尺背侧, 距离月骨窝和乙状切迹各约 5 mm 处钻孔。在尺侧腕屈肌腱桡侧做掌侧纵行切口, 切取全长掌长肌腱, 将其一端通过桡骨隧道穿至掌侧, 再用止血钳经三角纤维软骨盘下方透过掌侧关节囊, 将其引至背侧。在尺骨颈和茎突隐窝之间钻孔。将 肌腱两个断端经尺骨隧道引至尺骨颈处, 再把其中一端绕过尺骨颈。将前臂置于中立位, 抽紧缝合肌腱。 术后长臂石膏固定前臂于中立位。 4周后更换为前臂石膏, 继续制动 4周。结果 所有患者术后均获得 9~24个月随访, 平均 14个月。术后没有感染及感觉神经支损伤等并发症。疼痛减轻, 握力增加。采用改 良 Mayo评分评估腕关节功能: 术前平均 69分, 术后平均 95分。 5例患者对手术结果 满意。结论 韧 带解剖重建术适用于无骨性关节炎的慢性 DRUJ不稳定, 术后腕关节功能改善明显。     

Stability of the distal radioulnar joint contributed by the joint capsule

PURPOSE: The distal radioulnar joint (DRUJ) capsule is assumed to be an important stabilizer of the DRUJ. There are few published data regarding the capsule and its specific contribution to stability of the DRUJ. METHODS: We analyzed the contribution of the joint capsule to DRUJ stability in a biomechanical study consisting of collection of force/displacement data from 16 adult human cadaveric upper extremities. Each specimen was subjected to anteroposterior translation testing of the radius relative to the ulna in 3 positions of forearm rotation (neutral, 60 degrees pronation, 60 degrees supination) by serial sectioning of the DRUJ capsule. The experimental conditions tested included intact capsule, sectioned dorsal capsule, sectioned volar capsule, and repaired capsule. RESULTS: Isolated dorsal capsule sectioning resulted in volar instability of the radius to the ulna primarily in the maximum pronated position. Significant dorsal instability of the radius was observed after isolated volar capsule sectioning in the maximum supinated position. The restabilizing effect of capsule shortening was observed near the maximums of forearm rotation. The additional stability owing to capsule shortening surpassed that of the distal radioulnar ligament at these positions. CONCLUSIONS: We showed the effect of capsular injury on DRUJ joint stability and the restabilizing effect of capsule shortening. The importance of the capsule to DRUJ stability should be considered when planning surgical procedures to restore the unstable DRUJ.     

The importance of the distal radioulnar joint for reconstructive procedures in the malunited distal radius fracture

Clinically most patients complain about ulnar sided wrist pain and limited forearm rotation following malunited distal radius fractures. Possible bony reasons consist of intraarticular incongruency, malalignment of the sigmoid notch of the distal radius or the ulna-plus-situation at the wrist level. A persisting luxation of the distal radioulnar joint (DRUJ) will present itself with complete loss of forearm rotation. The ligamentous or bony detachment of the triangular fibrocartilage complex (TFCC) will lead to instability of the DRUJ. Uncorrected, each of these components will lead to arthrosis of the DRUJ. The presence of arthrosis only allows salvage procedures for the DRUJ and will lead to functional loss. Reconstructive options consist of radius correction osteotomy, ulnar shortening osteotomy, reposition of a luxation and refixation of the TFCC. To chose the necessary reconstructive procedure, the individual pathological situation has to be analysed.     

Irreducible fracture-dislocation of the distal radioulnar joint secondary to entrapment of the extensor carpi ulnaris tendon

Entrapment of the extensor carpi ulnaris (ECU) tendon between the ulnar head and the sigmoid notch of the radius occurred in a 12-year-old boy. This led to an irreducible dorsal dislocation of the distal radioulnar joint (DRUJ). Irreducible DRUJ dislocations are uncommon, and the entrapped ECU has not been previously described in a skeletally immature patient. The physical and roentgenographic findings of a dorsally displaced ulna, a widened DRUJ, and the inability to obtain a closed reduction should alert the examiner to the need for exploration. A dorsal exposure is required to free the ECU and reconstruct the triangular fibrocartilage complex.     

Sigmoid notch osteoplasty for chronic volar instability of the distal radioulnar joint: a case report.

Chronic recurrent volar dislocation of the distal radioulnar joint is a rare condition for which many operative procedures have been described. We describe a case of painful dislocation on supination. Investigation of the distal radioulnar joint revealed the absence of degenerative arthritis and a flat sigmoid notch that permitted dislocation. The case was successfully treated by osteoplasty of the volar lip of the sigmoid notch to create a buttress that prevented volar dislocation.     

Simultaneous dislocations of the radiocapitellar and distal radioulnar joints

Posttraumatic instability of the distal radioulnar joint (DRUJ), occurring in isolation or in association with fractures of the radius, is well-documented. Few reports have identified simultaneous ipsilateral DRUJ instability and elbow dislocation. The authors of the present study describe a case of persistent radiocapitellar subluxation after closed reduction of an elbow dislocation, secondary to irreducible volar subluxation of the DRUJ.     

Biomechanical function of the distal radioulnar and ulnocarpal wrist ligaments

PURPOSE: This study was designed to provide quantitative information concerning the functions of the ligaments that stabilize the distal radioulnar joint (DRUJ). This joint permits the radius to rotate around a nearly fixed ulna allowing supination and pronation of the hand. Understanding their function is important in developing procedures for reconstruction. METHODS: Using a ligament tension transducer that hooked under the center of the ligament and deflected it laterally while measuring the force required, we determined the tensions in 6 ligaments in 9 cadaver arms in pronation and supination of the hand. These ligaments included those of the DRUJ: palmar distal radioulnar ligament (PDRUL) and dorsal distal radioulnar ligament (DDRUL); and the ulnocarpal joint ligaments: ulnolunate ligament (ULL), ulnotriquetral ligament (UTL), and the ulnocarpal collateral ligament (UCCL), which includes the subsheath of the extensor carpi ulnaris, and the dorsal ulnocarpal ligament (DUCL). RESULTS: For the ligaments of the DRUJ in supination, the mean tension in the PDRUL (2.6 N) was greater than that of the DDRUL (0.8 N), whereas in pronation the mean tension in the PDRUL (1.1 N) was less than that of the DDRUL (1.7 N). For the ulnocarpal ligaments in supination, the ligament tensions in the ULL, UTL, and the UCCL were significantly greater than the same ligaments with the forearm pronated. The DUCL tension remained unchanged throughout supination and pronation. CONCLUSIONS: In supination of the forearm all ligaments except for the DDRUL had equivalent tensions, indicating their role in stabilizing the joint to this motion. In pronation ligament tensions generally were lower but were distributed over all 6 ligaments tested. DUCL tension was equivalent in both supination and pronation, unlike the other ligaments that had greater tensions in supination.     

Use of free vascularized fibular graft for congenital ulnar pseudarthrosis: surgical decision making in the growing child

Congenital pseudarthrosis of the ulna may cause growth disturbance and progressive forearm deformity, leading to functional compromise of the upper extremity. Treatment is challenging, and surgical decision making must take into account three goals of treatment: bony healing, distal radioulnar joint (DRUJ) stability, and continued skeletal growth. Four cases of congenital ulnar pseudarthrosis treated with free vascularized fibular graft are presented here. In two cases, the vascularized fibular graft included the proximal fibular epiphysis to reconstruct the DRUJ and ulnocarpal joints. Average age of the four patients at time of vascularized fibular grafting was 10 years (range 3-16 years). Patients had undergone up to three previous failed operations. A step-cut osteotomy technique with rigid internal fixation was used in all patients. Donor-site distal tibiofibular arthrodesis was performed in skeletally immature patients when appropriate. At average follow-up of 60 months (range 33-83 months), all patients achieved bony union with full wrist range of motion compared with the contralateral extremity. The DRUJ was stable in all patients. Two skeletally immature patients with concomitant epiphyseal transfer showed continued skeletal growth. Two patients nearing skeletal maturity achieved revascularization of the distal ulna. Free vascularized fibular grafting is a successful option in the treatment of congenital ulnar pseudarthrosis. Reconstruction of the distal radioulnar and ulnocarpal joints using concomitant proximal fibular epiphyseal transfer should be considered in the skeletally immature patient with distal ulnar involvement.